During screen light-on of a display device, respective voltages in a display panel must conform to a designated timing sequence in order to make a display screen operate normally. At present, during screen light-on, a light-on device is usually adopted to convert an operating voltage, thereafter to output respective voltages used to control a timing sequence of screen light-on. However, the light-on device adopted at present cannot realize adjustable delaying with respect to an output voltage during conversion of the operating voltage, and cannot meet a power-up timing sequence requirement of the display device.